Atomic and ionic size across the periodic table

Answer Key - Grade 10 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Magnesium's atomic radius is 150 pm and aluminum's is 125 pm (Slater). How many pm smaller is aluminum, Bo?

   25 pm
2. 2.

   Aluminum's atomic radius is 125 pm and silicon's is 110 pm (Slater). How many pm smaller is silicon, Esme?

   15 pm
4. 3.

   Using the table, which atom is largest, Jun?

   • Sodium
   • Silicon
   • Cesium
5. 4.

   Using the table, what happens to radius across period 3, Kira?

   Use the picture in question 3.

   • It stays the same
   • It grows
   • It shrinks
6. 5.

   Using the table, what happens to radius down group 1, Luz?

   Use the picture in question 3.

   • It stays the same
   • It grows
   • It shrinks
7. 6.

   Why do atoms get smaller across a period, Milo?

   • They lose shells
   • More protons pull the same shell in
   • They gain electrons and swell outward
8. 7.

   Chlorine and sodium both use shell 3. Why is chlorine smaller, Noah?

   • Its extra electrons make it bigger
   • Its 17 protons pull harder
   • It has fewer shells
9. 8.

   How many shells do the atoms across period 3 have, Pia?

   • One more each step
   • Three each
   • Eight each
10. 9.

    Why do atoms get larger down a group, Ren?

    • Each adds a new shell
    • Each loses protons
    • Their nuclei swell up in size
11. 10.

    Why is potassium larger than sodium, Tala?

    • It has fewer protons inside
    • It is a gas
    • It has one more shell